Generalization curve

See also: Machine learning terms

=Introduction

Machine learning strives to build models that accurately predict unseen data. To do this, machine learning models are trained on a dataset consisting of input features and their corresponding target values. Unfortunately, the performance of the model on this training dataset does not guarantee its performance when faced with new information - known as overfitting. To address this issue, evaluation of the model's performance on another dataset called the validation set must take place.

The generalization curve is a graph that displays the model's performance on training and validation sets as a function of model complexity. It can be used to identify the optimal level of complexity that balances bias-variance tradeoff while avoiding overfitting.

The Bias-Variance Trade-Off

Machine learning models use the bias-variance trade-off as a fundamental concept that describes the relationship between their ability to fit training data and generalize to new data. Model bias refers to any errors caused by assumptions made in the model, while variance refers to model sensitivity to fluctuations in training data. A model with high bias will not fit training data well while one with high variance overfits it by too much.

The bias-variance trade-off can be illustrated by the generalization curve, which displays the model's performance on training and validation sets as a function of model complexity. Model complexity indicates how flexible the model is; typically, this number of parameters determines its flexibility.

Generalization Curve

The generalization curve is a graph that displays the model's performance on training and validation sets as a function of model complexity. The x-axis represents model complexity, while the y-axis displays its performance on both sets. Accuracy, mean squared error, or area under the curve are typically used to measure this phenomenon.

The generalization curve can be used to identify the optimal model complexity that balances bias-variance tradeoff. A model with low complexity has high bias but low variance, while one with high complexity has both low bias and high variance. The optimal level of complexity will be identified as the point on the generalization curve where validation error is lowest.

The generalization curve can also be used to detect overfitting, which occurs when a model exhibits low training error but high validation error. Overfitting may be caused by either too complex a model or by having too small of a dataset. By recognizing when your model starts overfitting, you may be able to select an easier alternative or collect more data.

Explain Like I'm 5 (ELI5)

Machine learning is the process by which computers learn how to do certain things, like recognize pictures or comprehend language. Unfortunately, sometimes they may become too dependent on examples provided and forget how to tackle new challenges. Spelling something incorrectly can be like a kid who knows how to spell "cat," but doesn't know how to spell "dog." In order to ensure our computer doesn't forget how to do things it hasn't seen before, we test it on different examples that it has never encountered before. We can create a graph to demonstrate how well the computer performs on tasks it has previously encountered and those it hasn't. This graph, known as the generalization curve, helps us determine the most effective way to teach the computer new material without forgetting its existing skillset.

Explain Like I'm 5 (ELI5)

Imagine you own a toy car that you use to race around your room. To perfect your driving, you practice by driving it over different surfaces such as carpet, wood and tile.

After practicing on an unfamiliar surface like a bumpy rug, you discover that even with limited control you can still maneuver the car quite well - this is similar to the generalization curve in machine learning!

Machine learning allows a computer to learn how to recognize pictures of cats by studying many pictures and recognizing what features they all share.

Once the computer has perfected recognizing cats, we give it an unfamiliar picture of a feline. If the computer can still recognize the same cat in this new image, we say that it has "generalized" its knowledge to this new scenario.

The generalization curve illustrates how well a computer can recognize cats in new images that it hasn't seen before, similar to how well you might drive your toy car on surfaces you haven't practiced on before.